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NAME

r.li.patchnum - Calculates patch number index on a raster map, using a 4 neighbour algorithm.

KEYWORDS

raster, landscape structure analysis, patch index

SYNOPSIS

r.li.patchnum
r.li.patchnum --help
r.li.patchnum input=name config=name output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog

Parameters:

input=name [required]
Name of input raster map
config=name [required]
Configuration file
output=name [required]
Name for output raster map

Table of contents

DESCRIPTION

r.li.patchnum calculates the "patch number index" as:
f(sample_area)= Patch_Number

This index is calculated using a 4 neighbour algorithm, diagonal cells are ignored when tracing a patch.

NOTES

Do not use absolute path names for the config and output file/map parameters. If the "moving window" method was selected in g.gui.rlisetup, then the output will be a raster map, otherwise an ASCII file will be generated in the folder C:\Users\userxy\AppData\Roaming\GRASS7\r.li\output\ (MS-Windows) or $HOME/.grass7/r.li/output/ (GNU/Linux).

If the sample area contains only NULL values then it is considered to have zero patches.

EXAMPLES

To calculate patch number index on map my_map, using my_conf configuration file (previously defined with g.gui.rlisetup) and saving results in my_out, run:
r.li.patchnum input=my_map conf=my_conf out=my_out

Forest map (Spearfish sample dataset) example:

g.region raster=landcover.30m -p
r.mapcalc "forests = if(landcover.30m >= 41 && landcover.30m <= 43,1,null())"
r.li.patchnum input=forests conf=movwindow7 out=forests_patchnum_mov7
r.univar forests_patchnum_mov7

Forest map (North Carolina sample dataset) example:

g.region raster=landclass96 -p
r.mapcalc "forests = if(landclass96 == 5, 1, null() )"
r.li.patchnum input=forests conf=movwindow7 out=forests_patchnum_mov7

# verify
r.univar forests_patchnum_mov7
r.to.vect input=forests output=forests type=area
d.mon wx0
d.rast forests_patchnum_mov7
d.vect forests type=boundary

SEE ALSO

r.li - package overview
g.gui.rlisetup

REFERENCES

McGarigal, K., and B. J. Marks. 1995. FRAGSTATS: spatial pattern analysis program for quantifying landscape structure. USDA For. Serv. Gen. Tech. Rep. PNW-351. (PDF)

AUTHORS

Michael Shapiro - CERL (patch identification)
Markus Metz (statistics)

Last changed: $Date: 2014-12-19 13:17:36 -0800 (Fri, 19 Dec 2014) $

SOURCE CODE

Available at: r.li.patchnum source code (history)


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